Hands-on Activity:
    Compare the Aspirins

    You will be given a brand name aspirin product and a generic aspirin product with which to carry out this activity.

    1. Using the information on the label of each, calculate the percentage of acetylsalicylic acid in each type of tablet. Then calculate the cost per gram of acetylsalicylic acid in each tablet. Which gives you more bang for the buck, the brand name or the generic material? Explain your answer in your own words.

    2. Using the same brand name aspirin product and generic aspirin product, weigh 20 tablets from each of the two batches using a 1.0 mg balance or top-loader. Using the program on your calculator or the formula (given below), calculate the standard deviation of mass of a single value. What is the significance of the standard deviation, s? Which has more quality control, the generic material or the brand product? Explain your answer in your own words.

    Formula for standard deviation (s) of a single value:

    where d is the difference between each value and the average value, xa – m; n is the number of determinations.

    In nonstatistical terms, suppose a set of 10 aspirin tablets is measured thus:

    Tablet mass
    x (g)
    d = x – m
    d2
     
    0.4325
    –0.0021
    		0.00000441
    0.4322
    –0.0024
    		0.00000576
    0.4457
    +0.0111
    		0.00012321
    0.4298
    –0.0048
    		0.00002304
    0.4355
    +0.0009
    		0.00000081
    0.4367
    +0.0021
    		0.00000441
    0.4402
    +0.0056
    		0.00003136
    0.4288
    –0.0058
    		0.00003364
    0.4279
    –0.0067
    		0.00004489
    0.4368
    +0.0022
    		0.00000484

     
    Average mass m
    0.4346
    S d2
    		0.00027637

    The standard deviation is shown on a Gaussian curve below.



    A Gaussian curve, with s and m shown.

     

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      This activity was suggested by Dene Ryan, Bergen Academies.
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